Seeking to expand its family of civil helicopters by adding a six-seat aircraft to its two-/three-seat Model 269/300 series and four-/five seat Model 500 series without having to make a major investment of capital, in mid-1981 Hughes proposed a 'wide-body' version of the Model 500. The new model was to have a 38cm longitudinal plug inserted in the fuselage but was to retain the powerplant installation, rotor system, tail boom and T-tail surfaces, and most of the fuselage of the Model 500D virtually unchanged.

Market conditions were not favourable in late 1981 and early 1982 for the launch of a new helicopter. Moreover, the corporate re-organization and the decision of the parent organization, The Hughes Corporation, to divest itself of Hughes Helicopters, Inc, also made the development of a new product ill advisable. Consequently, all work on the Model 600X was terminated before Hughes Helicopters was acquired by McDonnell Douglas Corporation.

I was in the MD500 commercial engineering and later the program office during this period. What you are calling a 600X was never built. For an HAI convention, a mockup of it was built to "test the water". An old fuselage was cut in half longitudinaly and a composite "plug" added to widen it to three seats in both the front and back, thus the 6 hundred designator. New Model 500 components were used to complete the interior. A mast and doghouse was included but no main rotor blades or tail boom and no landing gear. It sat on a plywood platform so convention goers could walk up to it and sit in it. With little interest in the concept, Hughes Helicopters(McDonnel Douglas after 1984) gravitated towards what became the MD900 Explorer and by mid 1986 a fulltime program manager was at work championing that aircraft. The 600 numerical designator was later used on the stretched MD520N (NOTAR) and is presently offered by MD Helicopters, which is the successor to Hughes, McDonnel Douglas and Boeing. However the MD600, prsently being sold by MD Helicopters is stretched longitudinaly not lateraly. To the best of my recollection, absolutely NO engineering was ever done on what you are calling the 600X and it doesn't really qualify as ever being a helicopter, just a marketing tease to test the interest. During the same period, Hughes engineering came up with the 500J model which was to be a regular MD500E but with the longer MD530F main rotor blades and the required "F" model tail- boom extension to accomodate those longer blades. The Allison C20B engine was retained in the "J". This aircraft was to have improved performance in high and hot conditions and increase the gross weight and useful load, over the 500E with very little investment. Although much of the engineering was done, the Company never pursued it and none were built...a lost opportunity?

John Harding, e-mail, 13.05.2008

I would like to find out if there was a protype that was built of the Hughes 600X ? I like the design by adding that 38cm longitudial plug to it makes it a wide body is there any blueprint for the specification? it looks real close to the Liberity 2500T maybe some slight changes to the front fusalage nose area.

Any information about the designer it would be neat if the company that owns them if they would consider building this helicopter with the notar system or if this could be something they would look at being built as a certified kit on a amature level.